Central-energy telephone system.



PATENTED MAY 5,' 1903.

K. B. MILLER. CENTRAL ENERGY TELEPHONE SYSTEM.

APPLIOATION FILED NOV. 26, 190n0.

2 SHEETS-SHEET 1.

I0 MODEL.

0,. wnsnmcrm D c PATENTED MAY 5, 1903.

K. B, MILLER. CENTRAL ENERGY TELEPHONE SYSTEM.

APILIGATION FILED Novi. 26, 190`0.l

2 SHEETS-SHEET 2.

H0 MODEL.

No. 726,964. l

UNITED STA-TitsA Patented May 5, 1903.

PATENT FFICE.

KEMPSTER B. MILLER, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGGSWITCIIBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

CENTRAL-ENERGY TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 726,964, dated May 5,1903.

,Application led November 26, 1900. Serial No. 37,754. (No model.)

T0 all whom, t Htc/y concer-72,:

Be it known that I, KEMPsTER B. MILLER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Central-EnergyTelephone Systems,of which the following is afnll,clear, concise,andexact description,reference being had to the accompanyingdrawings,forn1ing a part of this specification. Y

My invention relates to a central-energy telephone system, my objectbeing to provide improved means whereby the talking-circuits and thesignaling-circuits at the central station may be effectively suppliedwith energizing-current from a centralized supply. It has been customaryheretofore in telephone systems of the general class to which thepresent invention relates to provide at the central station a commonbattery which snpplies current for the talking-circuits of the connectedsubscribers and also for the relays which control the supervisorysignals at the central station.

In accordance with the present invention, in the preferred form thereofI employ two batteries or sources of electricity, one adapted to beconnected in circuit with one of two connected subscribers lines -saythe callingsubscribers line-while the other is adapted to be connectedin circuit with the other connected subscribers line--to wit, thecalledsubscribers line-the two batteries, so far as the talking-currentsare concerned,being thus electrically separate and distinct. Thebatteries, however, coperate in actuating the relay which controls thesupervisory signals. The relay which controls the supervisory signals isso arranged that when the subscribers are in conversation the windingsof the relay will be traversed by currents from their respectivebatteries in such a direct-ion as to neutralize the relay-core, wherebythe signals remain quiescent. Should one of the subscribers alone hangup his telephone, the circuit through one ot' the batteries will beopened, thereby permitting the other battery to polarize the relay-coreto actuate one of the supervisory signals, depending upon whichsubscriber thus hangs up his telephone.

Should both subscribers hang up their telephones, a circuit is closedthrough the windings in such a manner as to actuate both of thesupervisory signals. I preferably employ the repeatingcoil interposedbetween the two connected lines as the relay for operating the'supervisory signals, as will be here inafter described.

I have illustrated my invention in the accompanying drawings, in which-Figure l is a diagram showing two subscribers telephone-lines and thecentral-station apparatusequipped in accordance with myinvention.Fig.2isadiagramshowingthe circuits when the subscribers are connectedfor conversation. Fig. 3 is a view showing diagrammatically the mannerin which the windings of the repeating-coil and relay are superimposed.Fig. 4 is a diagram showing the circuit for controlling the supervisorysignals to convey the clearing-out signal. Fig. 5 is a diagram showingthe manner of connecting the batteries with the plurality oftelephone-lines. Fig. 6 is a diagram showing a modification of myinvention.

Like characters refer to like parts in the several figures.

As shown in Fig. l, the line of subscriber A extends in two limbs a ctto the central station, where the limbs terminate in the linesprings a2a3, respectively, of the spring-jack. The spring a2 normally restsagainst contact c4 and the spring c3 against contact a5, between whichcontacts the battery b and individual annunciator c are connected. Thesubscriber is provided at the substation with the usual receiver d andwith a microphone d', connected directly in the circuit. The switch-hookd2 normally rests upon back contact d3, which is connected through belld4 to ground. When the receiver is removed from the hook, the sameengages contact d5 to close together the two limbs of the telephoneline.The subscriberB is provided with similar mechanism andis similarlyconnected with the central station, and I have employed the IOQVjack-belegging to subscriber A.

f phone-circuit.

nected by strand s through winding l, carried upon the core f, theopposite end of said winding being connected with battery g and thencethrough winding 2 to the tipstrand t, which is connected with the tip e.of the plug. Likewise, the callin g-plug h is provided with a tip h andasleeve h2, the former being connected by strand t' through therringing-key Z and thence through winding 4, battery g, and winding 3 tosleeve-strand s', which is connected with the sleeve h2. The windings 1and 2, which are connected with battery g, are wound upon the core insuch a direction that the current from the battery g traverses thetwowindings in a direction to add the magnetic etects thereof-that is, insuch a direction as to set up lines of force in the same direction inthe bent bar f on which they are wound, as is indicated by the arrowsadjacent said coils. Likewise, the windings 3 and 4, connected withbattery g', are adapted, when traversed by the current from batteryg',to add their magnetic effects in polarizing the core f, as shown bythe adjacent arrows. Opposite the poles of the corefsprings m o areprovided, the spring fm, carrying an armature adapted to rest oppositethe polef', while the spring 0 carries an armature adapted to restopposite the polefz. The armatures are polarized with like polarity-forinstance, with positive polarity. The springs m and o are connected withone side of the battery b, while the back contacts m' and o' thereof areconnected with the opposite side of the battery, the supervisorysignalor lamp rm2 being connected with the contact m and the lamp o2with contact o'. Each of the batteries g g preferably consists of aboutten cells of low internal resistance.

The spring Z of the ringing-key is adapted to vibrate between thecontacts Z and Z2, the latter being connected to ground through thecalling-generator Z3.

The operators telephone set Zt is connected in the usual manner betweenthe contacts Zo and k2, adapted to be connected with the oppositestrands of the cord connectors, to thereby bridge the operatorstelephone in circuit.

Supposing subscriber A desirous of conversing with the subscriber B, heremoves his i telephone-receiver from the hook, thus closing circuit ofbattery Z) through annunciator c to contact a5, spring a3, limb a', hookd2, contact CZ, limb a, spring a2, contact a4, back to the battery b.The individual annunciator c is thus actuated, thereby attracting theattention of the operator at the central station. The operator thereuponlifts answering-plug e and inserts the same in the spring- The springsa2 and a3 are-lifted from their contacts a4 and a5, respectively, andthe individual annunciator c is thus disconnected from the tele- As soonas the plug e is inserted the circuit of batteryg is closed throughwindings 1l and 2 and through the two limbs of the telephone-line, sincethe subscribers receiveris removed from the hook, and current is thuscaused to traverse windings 1 and 2 in such a direction as to impart topole f2 a negative polarity, while imparting a positive polarity to polef. The armature of spring o is thus attracted, thereby closing thecircuit of batteryb through spring o, contact o', and lamp o2, therebylighting the lamp. The operator now connects her telephone set incircuit in the usual manner and receives the number of the calledsubscriber. Learning that subscriber B is desired, she lifts the'calling-plug Zz, which is the companion to the the hook', the circuitof battery g' is closed through windings 3 and 4, which tend to polarizethe core fand in a direction opposite to that in which the windings 1and 2 tend to polarize the same, and the core is thus rendered neutraland inert. The armature of spring o is therefore released to open thecircuit thrcugh lamp 02,'and the lamp o2 is eX- tinguished to signify tothe operator that the called subscriber has answered and that theparties are in conversation.

The circuit during conversation is shown in Fig. 2. l/Vhen subscriber Ais talking, his microphone serves to vary the resistance of the circuitof batteryg, while when subscriber B is talking the resistance of thecircuit of battery g is varied.

In Fig. 2 the various parts are marked to correspond with similar partsshown in Fig. 1. As shown in Fig. 3, the windings'l and 4 aresuperimposed on the same leg of the bent bar f, while windings 2 and 3are superimposed on the other leg. Therefore any fluctuation of anelectric current in either of the circuits containing 1 and 2 or 3 and 4will be reproduced on the other circuit by the wellknown laws ofelectromagnetic induction. When, however, the resistance of the circuitot` subscriber A is being varied by the microphone at that station, thewindings 1 and 2 in series act together as a primary coil of aninduction-coil of which the secondary is formed by windings 3 and 4.When the microphone at station B is in action, windings 3 and 4 serve asthe primary coil and 1 and 2 as the secondary.

When the parties have completed their conversation, they hang up theirtelephonereceivers, thereby actuating the Vsupervisory signals to conveythe clearing-out signal to the operator.V If one of the subscribersalone hangs up his telephone,oneof the lamps alone will be lighted,while if both subscribers hang up their telephones both lamps willbelighted. Thus, if subscriber A hangs up his telephone, whilesubscriber B does not, the circuit of IOO IIO

battery g will alone be closed, and the core f will be polarized with anegative polarity at f' and positive polarity at f2, thereby lightingthe lamp m2 to signify to the operator that the subscriber A hascompleted conversation. Likewise, it' subscriber B hangs up histelephone, while subscriber A does not, the battery g will alone beincluded in circuit, and the windings l and 2 will produce a negativepolarity atf2 and a positive polarity at f', thereby lighting lamp o2.lf both subscribers hang up 'their telephones, then circuit will beclosed from the ground at substation A, through the bell d, over limb a'and strand t, through winding 2, battery g, conductor 5, battery g',winding 4, strandt', and limb ct' of subscriberB, through his bell toground. The windings 2 and 4 are thus energized, and as the windings areupon opposite legs of the core f and tend to polarize the coreoppositely the result will be that poles f' and f2 will be of negativepolarity, while a consequent pole will be formed at the bend of thecore. The armatures of levers rm and o will therefore be attracted toclose circuit through the'supervisory lamps m2 and 02. The circuit forthe clearing-out signal when both subscribers hang up their telephonesis shown in Fig. 4.

As shown in Fig. 3, I superimpose the windings mounted on each leg ofthe relay-core and wind each coil over the entire length of the leg.This construction renders the action as a repeating-coil more efficientand at the same time makes it possible for steady currents in onewinding to be completely neutralized by steady currents in the otherwinding on the same leg of the core. This neutralization of the core ofthe repeatingcoil is of material advantage in its effect upon theefliciency of the apparatus when acting as a repeating-coil, for iron ina neutral state is more susceptible to slight changes in magnetismcaused by varying currents than when the iron is strongly polarized inone direction or the other.

In Fig. 5 I have illustrated the manner in which a plurality of pairs ofconnected telephone-lines are associated with the pair of batteries. Thetelephone-lines A and B are connected through the windings l 2 3 4 ofthe repeating-coil, the battery g being in circuit with the windings 1and 2, while battery g' is in circuit with windings 3 and 4. Likewiselines C and D are connected through windings l 2fL 3'LL 4'"L of a secondrepeatingcoil and lines E and F through windings lb 2b 3" 4b of a thirdrepeating-coil. One line of each connected pair is thus connected withbattery g, while the other line of each pair is connected with batteryg. In practice I preferably connect all ot' the answering-plugs with oneof the batteries-say battery g-and all of the calling-plugs with theother battery, gh

In Fig. 6 I have shown a modification ofthe relay in which an armatureis provided on the spring p and mounted opposite the bend of the core f.This spring p is connected with one pole of the battery b and is adaptedwhen attracted by the consequent pole developed at the bend of the coreto'engage contactspp2,the former being connected through lamp m2 to theopposite pole of the battery, while the latter is connected through lamp02. The springs m and o are formed integral and pivoted, so that but onecan engage its contact m' or o at a time. When circuit is closed throughbut one of the batteries g or g', one or the other of the lamps m2 o2will be lighted, as above described. When both subscribers han g u ptheir telephones to send the clearingout signal, a consequent pole isdeveloped at the bend of the core, and spring@ is attracted, therebyclosing circuit through lamps m2 and o2.

Having described my invention, what I claim as new, and desire to secureby Letters APatent, is-

1. The combination with a plurality of telephone-lines, each having amicrophone connected directly'in circuit at the substation, ot means forconnecting any two of the lines together in pairs for conversation, arepeatingcoil interposed between the lines of each connected pair, and apair of common sources of electricity at the central station, one sourceplaced in circuit with each line of each pair and a winding of saidrepeating-coil by the act of establishing the connection forconversation, substantially as described.

2. The combination with a plurality of telephone-lines, terminating at acentral office', of means for connecting the same together in pairs forconversation, and a pair of sources of electricity common to theplurality of lines, one adapted to be included in circuit with each lineof a connected pair by the act of establishing the connection,substantially as described.

3. The combination with a plurality of telephone-lines, of means forconnecting the same in pairs for conversation, a pair of sources ofelectricity common to the plurality of lines and connected therewith inthe act of establishing connections, one adapted to be ineluded incircuit with the lines of the calling subscribers, and the other incircuit with the line of the called subscribers, substantially asdescribed.

4. The combination with a plurality of telephone-lines, of a pluralityof cord connectors for connecting the same in pairs, and a pair ofsources of electricity, one member of each cord connector beingconnected with each et said sources of electricity, whereby said sourcesare common to the plurality of lines and are connected therewith by theact of establishing the connections, substantially as described.

5. The combination with a plurality of telephone-lines, of a pluralityof pairs of connecting-plugs,a repeating-coil interposed between theplugs of each pair, and a pair of sources IIO of electricity, one plugof each pair being connected in circuit with one of said sources and theother plug of each pair in circuit with the other source, substantiallyas described.

6. The combination with a plurality of telephone-lines, of a pluralityof pairs of connecting-plugs,arepeating-coilinterposed between the plugsof each pair, each winding of each repeating-coil being divided into twoparts, and a pair of sources of electricity, one interposed between thetwo parts of each winding connected with the answering-plugs, and theother source interposed between thetwo parts of each winding connectedwith the callingplugs, substantially as described'.

7. In a telephone-exchange system,the combination with a plurality oftelephone-lines, each having a transmitter at the substation connectedin circuit with its main line, of a cord-circuit at the central officeto inductively unite said lines in pairs for conversation, two sourcesof current-supply arranged to be connected in circuit with the said mainlines by the act of uniting the lines for conversation by means of thesaid cord-circuit, one source with one line of the connected pair andone source with the other line of the pair, whereby each of the twoconnected main lines is independently supplied with current from aseparate source for conversational purposes, substantially as described.

8. In a telephone-exchange system,the combination with a plurality oftelephone-lines, each having a transmitter at the substation connecteddirectly in its main-line circuit, of a suitable calling-signal for eachsaid line at the central ofce and rendered inoperative when a connectionfor conversation is made with the said line, a cord-circuit at thecentral office to inductively unite said lines for conversation, twosources of current-supply arranged to be connected in circuit with thesaid main lines by the act ot' uniting the lines for conversationthrough the medium of the cord-circuit, one source of current with oneline of the connected pair and the other source with the other line ofthe pair, whereby each of the two connected main lines is independentlysupplied with current from a separate source for conversationalpurposes, substantially as described.

9. In atelephone-exchange systexn,the com'- bination with a plurality ofmetallic-circuit telephone-lines, each having a transmitter at thesubstation connected in the main circuit of the metallicline, of acord-circuit at the central ottice to inductively unite said lines inpairs for conversation, two sources of current arranged to be connectedin circuitwith the said metallic lines by the act of uniting the linesfor conversation through the medium of said cord-circuit, one source ofcurrent being connected with one line of the united pair and the othersource with the other line of the pair, whereby each of the twoconnected metallic lines is independently supplied with current forconversational purposes from a separate source of supply, substantiallyas described.

10. In a telephone-exchange system, thev combination with a plurality ofmetallic telephone-lines, each having a transmitter connected directlyinthe-metallic line at the substation, of a suitable calling-signal foreach line at the central office, means lto render the said signalinoperative when a connection for conversation is made with the saidline, a cord-circuit at the central office to inductively unite saidlines in pairs for conversation, two sources of current-supply at thecentral office arranged to be connected in circuit with the saidmetallic lines by the actof uniting them together for conversationthrough the medium of the cord-circuit, one of said sources of currentbeing connected with one line of the united pair and the other sourcewith the other line ot' the pair, whereby each of the two connected mainlines is independently supplied with current for conversational purposesfrom a separate source, substantially as described.

11. ln a telephone-exchange system, the combination With a plurality ofmetallic telephone-lines, each having a transmitter at the substationconnected directly in circuit with its main line, of a suitablecalling-signal for each said line at the central ofce, said signal beingrendered inoperative when a connection for conversation is made with thesaid line, a plurality of cord-circuits at the central ofcetoinductivelyunite said linesin pairs for conversation, two sources ofcurrent-supply at the central ottico arranged to be connected in circuitwith said pairs of main lines by the act of uniting the lines togetherforconversation through the medium of the cord-ci rcuits, one of saidsources being thereby connected with one of the lines of each pair andthe other source with the other line of the pair, whereby each of thetwo connected main lines is independently supplied with current from aseparate source for conversational purposes, said two sources of currentbeing com- IOO IIO

mon to the plurality of cord-circuits, substantially as described.

12. In av telephoneexchange system, the combination with a plurality oftelephonelines, each having a transmitter at the substation connecteddirectly in its main-line circuit, of a calling-signal for each saidline at the central ofce, a central source of current common to thelines and normally connected therewith to control the operation of saidsignals, said signals being rendered inoperative when a connection forconversation is established with the lines, a plurality of cord-circuitsat the central ofiice to inductively unite said lines in pairsforconversation,two sources of current-supply arranged to be connected incircuit with the pairs of main lines by the act ot connecting thecord-circuits with the lines, one of said sources being connected withone line of each kunited pair and the other source with the other lineof the said pair, whereby each of the two lines of the united pairs isindependently supplied with current from a separate source forconversational purposes, said two sources of current being common to thesaid plurality of cordcircuits in the order named, substantially asdescribed.

13. The combination with a pair of telephone-lines, of a separate sourceof electricity in circuit with each line, a relay having a core and anarmature opposite each pole thereof, said armatures being polarizedalike, a signaling device controlled by each armature, and windings onsaid core one in circuit with each source and arranged to neutralize thecore when both sources are in circuit, substantially as described.

14. The combination with a pair of telephone-lines, of a separate sourceof electricity in circuit with each line, a combined relay andrepeating-coil having a core and an armature opposite each pole thereof,said armatures being polarized alike, a signaling device controlled byeach armature, and windings on said core one in circuit with each sourceand arranged to neutralize the core when both sources are in circuit,substantially as described.

15. The combination with a pair of telephone-lines, of a separate sourceof electricity in circuit with each line, a relay having a core and anarmature opposite each end thereof, said armatures being polarizedalike, a signaling device controlled by each armature, a pair ofwindings on said core onein circuit with each source a part of eachwinding being mounted on opposite ends of said core, and said windingsbeing so distributed and arranged on said core as to neutralize the corewhen both sources are in circuit, substantially as described.

16. The combination with a pair of telephone-lines, each having twolimbs, of a separate source of electricity in circuit with each line, arelay having a core and an armature opposite each pole thereof, saidarmatures being polarized alike, a signaling device controlled by eacharmature, a pair of windings on said core, one in circuit with eachsource, lpart of each pair being mounted on opposite ends of said core,said several windings being arranged to neutralize the core when bothsources are connected in their individual circuits, and means actuatedby the hanging up of both subscribers telephones for closing circuitthrough said sources in series and through one winding on each end ofsaid core to attract bot-h armatures, substantially as described.

17. The combination with a pair of telephone-lines and a signal, of apair of sources of electricity adapted to be individually included inthe circuits of the telephone-lines for talking purposes and actingconjointly to control said signal,substantially as described.

18. The combination with a pair of telephone-lines joined by arepeating-coil, of a pair of sources of electricity at the centralstation one in circuit with each line, and a signal controlled by theconjoint action of said sources of electricity, substantially asdescribed.

19. The combination with a pair of tele phone-lines, of a pair ofsources of electricity, means for including said sources of electricity,one in circuit with each of said lines, and for including both of saidsources of electricity in series in a common circuit, and a signalcontrolled by said sources of electricity, substantially as described.

20. The combination with a pair of telephone-lines, of a pair of sourcesof electricity, means for including said sources of electricity, one incircuit with each of said lines, at one time and under certainconditions of use and for including both of said sources of electricityin series in a common circuit at another time and under othercircumstances of use, and a signal controlled by said sources ofelectricity, substantially as described.

21. The combination with a pair of telephone-lines, of a pair of sourcesof electricity, means for including one of said sources of electricityin each of said lines, and for including both of said sources in seriesin a circuit including both lines, and a signal controlled by saidsources, substantially as described.

22. The combination with a pair of metallic-circuit telephone-lines, ofa pair of sources of electricity, means for including one of saidsources of electricity in circuit with each of said telephone-lines, andfor including both of said sources of electricity in a circuit includingin series one limb of each of said lines, and a third conductor, and asignal adapted to be controlled by said sources of electricity,substantially as described.

23. The combination With a pair of telephone-lines united through arepeating-coil, of a pair of sources of electricity, one in circuit witheach of said lines, a signaling device comprising a magnet having aWinding in circuit with each of said lines, said Windings being arrangedto neutralize each other when both sources of electricity are in closedcircuit and to energize said magnet when one of said sources alone is incircuit, substantially as described.

In Witness whereof I have hereunto subscribed my name in the presence oftwo witnesses.

KEMPSTER B. MILLER. Witnesses:

WILLIAM -W. DEAN, T. W. DUNBAR.

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